The present invention relates to a device for coding locations in a transportation network, information concerning the locations being transmitted from one transmitter to one receiver, and to a device for decoding received information, which signifies a location on a street and contains a plurality of coordinate pairs, each of which is given a tolerance range and of which at least one specific coordinate pair along with its tolerance range includes the location.
In traffic control engineering systems, vehicles exchange information with central systems Via remote data transmission. This information exchange enables different applications, such as emergency call service, or, traffic information service, or, help with directions or dynamic guidance services, to be implemented. The transmission of location information is necessary for all these services. Location information can be used, for example, to depict the positions of vehicles, location and extent of traffic jams and destinations or selected intermediate points of a driving route.
The information exchange can also use intermodal mobility services, which permit linking of different means of transportation, for example, automobile travel and public transportation. In this case, location information would be useful, for example, as an interface between one transport operator and the other.
In the exchange of location information, different degrees of precision are required depending on the particular service. For example, an emergency call service requires a higher degree of precision in the specification of a location than does a traffic information service. In the interplay between a traffic control engineering central system and the vehicles, a unique understanding of the location information is therefore necessary. If, for example, the central system transmits hotel A as the destination for the route of a vehicle, then the vehicle navigation system must not route the vehicle to hotel B.
Because of the ultimately limited capacity of the means of transmission between central system and vehicle, an effective coding of the location information is required. However, a transmission of geographic coordinates by itself is not sufficient since different locations can be found at one geographic position, for example, on bridges or in tunnels. Moreover, not all locations are punctiform; therefore, it is usually necessary to also indicate a direction.
For coded transmission of locations, information used for coding and decoding is contained in read-only-memory in both the vehicle and the central system. For a traffic information service, the transmission of a code xe2x80x9cED73EF5xe2x80x9d, for example, using a read-only memory within the device can lead to the output of the text xe2x80x9cA5 from Basel to Karlsruhe at junction 58 Herbolzheimxe2x80x9d. For decoding, the location, being addressed must therefore be present in the read-only memory. Additional information that is not required for the decoding itself, for example location names and street numbers, can also be stored for the individual locations, and therefore does not need to be uniquely determined between central system and vehicle. A key-based coding system of that type is, for example, the coding of location information in the TMC system according to CEN ENV 12313-3. An important feature of the location database used in that system is that references are made to adjacent locations. Because of those references, among other things, the maintenance and synchronization of this location database is technically critical. However, received information can only be coded if the same location database has been used for the coding.
An object of an exemplary embodiment present invention is to specify a device for coding locations that permits decoding of location information in the receiver even for different coding and decoding tables. The exemplary embodiment of the present invention can be used for several of the aforementioned services.
An exemplary embodiment of the present invention provides that: This objective is met according to the present invention in that
the coordinate portion includes a plurality of coordinate pairs, one coordinate pair representing the coordinates of the coded location stored on the transmitter side and at least one other coordinate pair representing at least one auxiliary point, and
the declaration portion includes at least the number of coordinate pairs contained in the coordinate portion, the position of the coordinate pair of the coded location in the coordinate portion and a type indication of the coded location.
Another exemplary embodiment of the present invention provides that the declaration portion also can contain indications for the type of coding and for tolerances of the coordinate pairs.
In the exemplary embodiment of the present invention, road systems, route networks for various means of transport (rail, bus, plane), rail systems and waterway systems, thus, all networks in which places can be described in relation to each other using geographic coordinates ultimately fall under the meaning of transportation networks. In this context, even locations that belong to different transportation networks can be addressed using the coding according to the present invention.
In another exemplary embodiment of the present invention, a user can be guided on a Saturday morning as to what the fastest route in a pedestrian zone may be, the fast route can incorporate a bus or train into the consideration of the best solution. In addition to established points in the road system, for example addresses or intersections, other types of locations, such as a traffic jam within the road system or a streetcar stop on a streetcar line, may be considered as locations to be coded.
The exemplary embodiment of the present invention also provides that an exactly defined location can be coded in spite of the limited degree of precision of the transmitted coordinates. It is not assumed that the location databases of the transmitter and receiver have an identical structure. All that is required is an assignment to the contents by indicating the geographic coordinates.
A rough similarity of the street elements defined using the step-by-step process of the exemplary embodiment of the present invention is sufficient for decoding. In this context, the depth of detail in the receiver must at least correspond to the depth of detail of the location database of the transmitter. Moreover, the relationships between the points that are assumed on the transmitter side when selecting the points must be reproducible for the receiver. For example, all points can lie on one street. In this case, these streets and the points situated on them must be known in the receiver and in the transmitter. The individual steps in the system according to the exemplary embodiment of the present invention form a maneuver to be performed on the basis of a route description that one would give to a stranger if asked for directions.
When using geographic coordinates, a declaration of the coding to be used is required. In this context the declaration can be performed explicitly or implicitly. In any of the exemplary embodiments of the present invention, the system can precede all location information described by a maneuver with information on the coding used. For this purpose, the declaration portion can be at least semi-permanently stored in the transmitter and in the receiver. A declaration portion of this type can be established, for example, in a standard that is valid for all transmitters and receivers.
In another exemplary embodiment of the present invention the declaration portion can be at least partially transmitted when communication is established between the transmitter and the receiver. Another exemplary embodiment of the present invention can further provide that the declaration portion is at least partially transmitted together with the coordinate portion and temporarily stored in the receiver. In this way, different declarations that are adapted to the particular circumstances can be transmitted from one location coding to another location coding.
One beneficial device for the decoding process includes an exemplary embodiment of a decoder device according to an exemplary embodiment of the present invention can include features that locations falling within the tolerance range of the received coordinate pairs are determined in a location database containing the coordinates, the position at any time on a traffic route and additional information about locations, that of the specified locations those situated on a common traffic route are selected, and that of the selected locations the one that falls within the tolerance range of the specified coordinate pair is defined as the decoded location.